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C C h h i i l l l l e e r r T T r r o o u u b b l l e e s s h h o o o o t t i i n n g g
6. Symptom: Compressor loses oil
Possible Causes
Low refrigerant charge
Gas velocity in risers too low
Oil trapped in line
Excessive compression ring blow by
Liquid refrigerant
7. Symptom: Low refrigeration suction pressure
Possible Causes
Lack of refrigerant
Evaporator dirty
Clogged suction line or suction gas strainers
Condensing temperature too low
Low water temperature
Compressor will not unload
Low discharge pressure
Expansion valve malfunctioning
Mis-adjusted or defective TXV
Receiver service valve closed
Compressor service valves closed
Clogged liquid line filter-drier
Excessive glycol concentration
Liquid line solenoid restricted or faulty
Insufficient chilled water
Restricted water/glycol line
Water/glycol mixture contaminated
Evaporator tubing clogged or fouled
8. Symptom: High refrigeration suction pressure
Possible Causes
Expansion valve opened too far
Excessive refrigerant charge
High water temperature
64
Potential Solutions
Check for leaks and repair. Add refrigerant to proper charge.
Check riser sizes against compressor gas flow
Check pitch of lines and refrigerant velocities
Replace or rebuild compressor
Check compressor superheat. Superheat at the compressor suction
should be approximately 15° F (8.3° C).
Potential Solutions
Check for leaks. Repair and add charge.
Clean chemically
Clean strainers
Check condensing temperature regulation system
Raise set point; check design specification
Replace solenoid or controller
Refrigerant charge; replace compressor
Reset for proper superheat (10-12 º SH)
Adjust or replace valve
Turn counterclockwise completely. Do not fully backseat if pressure
switch is installed on service port
Dangerous! Turn counterclockwise completely
Replace cartridges
Drain, refill (deionized water), retest
Replace solenoid valve, coil, or internals as necessary
Adjust flow rate across evaporator
Clean strainers; check manual and electronic valves
Intensive cleanup effort needed to identify source of contamination;
external filter may be required
Reverse flush with appropriate chemical solutions
Potential Solutions
Re-adjust to 10° to 12°
Creates high pressure alarms; reclaim excess refrigerant and verify
proper sub-cooling and superheat.
Low refrigerant charge; failing compressor; check design
specifications
ARTC-SVX001B-EN
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